CountPart
49 Bliptronics LED Pixel RGB 8mm (I got 2 × 12mm Diffused Digital RGB LED Pixels Strand of 25)
1 USB Boarduino v2.0
1 5V 2000mA Switching Power Supply

The 7×7 pixel grid is laid out and animated with the live LED Editor, already built at W=7, H=7, Zigzag - zigzag-wired, so each row connects straight into the next instead of a return wire back to the start.